In recent, the trend in golf is that it is spread as a leisure sport and gradually popularized.
In general, the golf is a game where competing players use golf clubs to hit golf balls on a spot in a golf course into holes spaced from the spot with a fixed distance, and victory and defeat is determined by the number of hitting of the golf ball until the ball enters the hole starting from the initial hitting position. For reducing the number of hitting of the golf ball, above all, it would important that the golf ball is accurately hit by the golf clubs to obtain desired direction and flying distance.
The way of hitting the golf ball includes T-shot, fairway wood shot, iron shot, approach shot, bunker shot, putting etc., and the golf clubs to be used and posture vary depending on each way of hitting. However, in case of basic swing motions for T-shot, fairway wood shot, iron shot etc., motions of back swing, down swing, impact, follow through etc. are continuously carried out. Herein, the back swing is a motion of lifting the golf club backward, and the down swing is a motion of swing the golf club downward. Then, the impact is the moment of hitting the golf ball by the golf club, and the follow through is a motion of naturally extending the golf club forward and upward while turning the waist to the left after hitting the golf ball by a head of the golf club.
For continuously and accurately carrying out the swing motions as described above, the player should have an good command of each motion. For this purpose, many training devices are disclosed for conveniently correcting the swing motions.
According to “golf club for training of swing” disclosed in Korean U.M. No. 0410215, the swing is exercised using weights as the head of the golf club. In this case, variation of centrifugal force only depends on acceleration of swing by user because the length of the golf club is fixed in swing, and therefore variation of hitting power between the time of starting of the swing and the time of hitting is not wide. Therefore, there is a problem that training of swing can not be effectively carried out for concentratively exhibiting the hitting power at an impact position. That is, there is also a problem that desired flying distance is difficult to obtain because training of swing for stable swing and exact hitting of the ball is difficult to carry out.